JP2000280341A - Thermoplastic liquid crystal polymer film and method for modifying the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic liquid crystal polymer film and a coverlay film having various excellent properties derived from a thermoplastic liquid crystal polymer and having high adhesive strength to an adhesive. SOLUTION: A thermoplastic liquid crystal polymer film having a degree of molecular orientation SOR in the longitudinal direction of the film in the range of 1.03 to 1.15, and a maximum surface roughness (Rmax; JIS B060).
1) using a metal foil having a thickness in the range of 1 to 3 μm, pressing the thermoplastic liquid crystal polymer film and the metal foil between heating rolls to form a laminate, and applying the laminate to the thermoplastic liquid crystal polymer. A modified step including a second step of modifying the film at a pressure of 5 to 20 kg / cm ² using a metal roll heated to a temperature equal to or higher than the melting point of the film, and a third step of peeling the metal foil from the laminate. Obtain a thermoplastic liquid crystal polymer film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film comprising a thermoplastic polymer capable of forming an optically anisotropic molten phase (hereinafter referred to as a thermoplastic liquid crystal polymer) (hereinafter referred to as a thermoplastic liquid crystal polymer film). And a coverlay film obtained by applying an adhesive to the modified thermoplastic liquid crystal polymer film. More specifically, the thermoplastic liquid crystal polymer film according to the present invention, in addition to various excellent properties derived from the material, also has excellent adhesive strength to an adhesive, and is useful as a circuit board material and the like. It is also useful as a coverlay film for protecting the wiring of a circuit board.

[0002]

2. Description of the Related Art As a raw material for a circuit board in the field of electronics, a metal foil laminate composed of a conductive metal foil and a film or sheet-like electric insulating material is used. Such a metal foil laminate has a double-sided metal foil laminate in which an electrical insulating material is sandwiched between two metal foils, and a single-sided metal foil laminate in which one metal foil and an electrical insulating material are joined. There are two forms. In order to obtain a circuit board from such a metal foil laminate, it is common to form a wiring circuit by chemically etching a metal foil. However, since the metal foil surface, which is a wiring circuit formed by etching, is easily oxidized, a protective layer is provided so as to cover the surface, and this protective layer is usually called a cover coat, a cover film, or a cover lay film. ing. The form of this protective layer is a thermosetting resin directly coated on the circuit pattern, a photocuring resin directly coated on the circuit pattern, an electric insulating film thermally bonded on the circuit pattern, and an electric insulating film. What adhere | attached on the circuit pattern with the adhesive agent is known. At this time, a method of using a coverlay film having a configuration in which a thermosetting adhesive is applied to an electrical insulating film made of the same material as the electrical insulating material of the circuit board and thermally bonding the coverlay film on the circuit pattern is performed by changing the wiring shape It is most often used because it can be flattened.

[0003] The thermoplastic liquid crystal polymer film used as an insulating material for the above-mentioned circuit board or the like is usually produced by extrusion molding. In the longitudinal direction (hereinafter referred to as MD direction) and the width direction perpendicular to the machine axis (hereinafter referred to as TD direction), physical properties such as tensile elastic modulus, mechanical strength, and thermal expansion coefficient are significantly different. It becomes an anisotropic film. For example, a film extruded using a T-die has extremely high mechanical strength in the MD direction, but has low mechanical strength in the TD direction and easily tears along the MD direction, so that it cannot be put to practical use as it is.

[0004] Further, due to the property of being easily oriented, layers of polymer molecules are stacked in the thickness direction. In this state, the film is easily peeled off from the film surface in a layered form (hereinafter, sometimes referred to as "in-layer peeling"), so that the adhesive strength to the adhesive is reduced. In addition, the extruded thermoplastic liquid crystal polymer film, in addition to the above-mentioned various problems, has poor affinity with a generally used thermosetting adhesive and has a low adhesive strength, so that practicality is significantly impaired.

[0005]

Therefore, in order to improve the adhesive strength of the film to the adhesive, a method has been attempted in which the surface of the film is roughened by giving irregularities to increase the surface area of the adhesive. For example, Japanese Patent Application Laid-Open No. 6-206254 proposes to provide a concave portion under specific conditions in order to improve the abrasion resistance generated in connection with the above-described delamination. In some cases, a sufficient adhesive force to the adhesive cannot be obtained. Also, an attempt was made to roughen the surface of the film by a general sandplast method in which the fine powder was hit on the film surface to damage the film surface. However, sufficient adhesion to the adhesive was not obtained.

Further, as a method for improving the surface characteristics of the film, there are methods such as corona irradiation treatment, electron beam irradiation treatment, and etching of the surface with a chemical. However, these methods also make the thermoplastic liquid crystal polymer film resistant to electromagnetic waves. It has excellent chemical and chemical resistance and is chemically stable,
No effect of modifying the film surface is observed.

Japanese Unexamined Patent Publication (Kokai) No. 6-177520 proposes that a thermoplastic liquid crystal polymer film is coated with an adhesive of a specific type and composition to form a flame-retardant coverlay film. According to this, a coverlay film having excellent electrical characteristics derived from the thermoplastic liquid crystal polymer film can be obtained. However, this cover lay film has a sufficient adhesive force between the adhesive and the electrical insulating material of the circuit board, but the adhesive force between the thermoplastic liquid crystal polymer film forming the cover lay film and the adhesive is sufficient. , Remain small because the properties of the film surface have not been improved.

The inventors of the present invention have conducted research on improving the adhesive strength of a thermoplastic liquid crystal polymer film to an adhesive, and have found the following. That is, using a thermoplastic liquid crystal polymer film having a specific range of molecular orientation degree SOR and a metal foil having a specific range of surface roughness, these are thermocompression bonded to form a laminate, which is then heat treated under specific conditions. When the metal foil is peeled off after the modification, the anisotropy is eliminated, and a thermoplastic liquid crystal polymer film having high adhesive strength to the adhesive is obtained. In addition, by using a thermoplastic liquid crystal polymer film, derived from this, (1) heat resistance, (2) low moisture absorption, (3) excellent thermal dimensional stability, (4) Sufficient features such as excellent humidity dimensional stability, (5) excellent high-frequency characteristics, (6) flexibility at low temperatures, and (7) excellent radiation resistance Can be demonstrated in.

Accordingly, an object of the present invention is to provide a method for improving the adhesive strength of a thermoplastic liquid crystal polymer film to an adhesive. Also, the other purpose is to provide various excellent properties derived from the thermoplastic liquid crystal polymer,
In addition, it is an object of the present invention to provide a thermoplastic liquid crystal polymer film having anisotropy eliminated and having a high adhesive strength to an adhesive and its use as a coverlay film.

[0010]

In order to achieve the above-mentioned object, a first aspect of the present invention is to provide a film having a degree of molecular orientation S in the longitudinal direction of a film.
A thermoplastic liquid crystal polymer film having an OR of 1.03 to 1.15 and a maximum surface roughness (Rmax; JIS B0
601) is a step of pressing a metal foil having a thickness in the range of 1 to 3 μm between heating rolls to form a laminate, and using a roll in which the laminate is heated to a temperature equal to or higher than the melting point of the thermoplastic liquid crystal polymer film. The present invention relates to a method for obtaining a modified thermoplastic liquid crystal polymer film, comprising a second step of modifying treatment at a pressure of 5 to ²⁰ kg / cm ² and a third step of peeling a metal foil from a laminate. In the second step, the first
It is preferable that the metal foil side of the laminate obtained in the step is brought into contact with a heated metal roll, so that the surface of the film to be bonded to the metal foil is surely modified.

In a second aspect of the present invention, after the first step of the first aspect of the invention is completed, as a second step, the laminate is subjected to non-pressurization in a heating furnace at a temperature not lower than the melting point of the thermoplastic liquid crystal polymer film. The present invention relates to a method for obtaining a modified thermoplastic liquid crystal polymer film by performing a heat treatment in a state and peeling a metal foil from a laminate in a third step.

According to each of the above-mentioned inventions, a thermoplastic liquid crystal polymer film having various excellent properties derived from the thermoplastic liquid crystal polymer, having anisotropy eliminated, and having excellent adhesion to an adhesive can be obtained. Can be

The raw materials of the thermoplastic liquid crystal polymer film used in each of the above-mentioned inventions are not particularly limited, but specific examples thereof include compounds classified into the following (1) to (4). And the known thermotropic liquid crystal polyesters and thermotropic liquid crystal polyesteramides derived from the derivatives thereof. However, in order to obtain a polymer capable of forming an optically anisotropic molten phase, it goes without saying that there is an appropriate range for each combination of the starting compounds.

(1) Aromatic or aliphatic dihydroxy compounds (see Table 1 for typical examples)

[0015]

[Table 1]

(2) Aromatic or aliphatic dicarboxylic acids (see Table 2 for typical examples)

[0017]

[Table 2]

(3) Aromatic hydroxycarboxylic acid (for typical examples, see Table 3)

[0019]

[Table 3]

(4) Aromatic diamine, aromatic hydroxyamine or aromatic aminocarboxylic acid (see Table 4 for typical examples)

[0021]

[Table 4]

Representative examples of thermoplastic liquid crystal polymers obtained from these starting compounds include copolymers (a) to (e) having the structural units shown in Table 5.

[0023]

[Table 5]

The thermoplastic liquid crystal polymer used in the present invention may have a temperature in the range of about 200 to about 400 ° C., particularly about 250 to about 350 ° C. for the purpose of imparting the desired heat resistance and processability to the film. Those having a melting point within the range are preferred, but those having a relatively low melting point are preferred from the viewpoint of ease of film production. Therefore, when higher heat resistance and a higher melting point are required, the obtained film is subjected to a heat treatment to increase the film to a desired heat resistance and a higher melting point. To explain an example of the condition of the heat treatment, even if the melting point of the obtained film is 283 ° C.,
Heating at 5 ° C. for 5 hours gives a melting point of 320 ° C.

The thermoplastic liquid crystal polymer film used in the present invention is obtained by extruding the above polymer.
At this time, any extrusion molding method can be used.
Die film forming and drawing methods, laminate drawing methods, inflation methods and the like are industrially advantageous. In particular, in the inflation method, stress is applied not only in the MD direction but also in the TD direction orthogonal to the MD direction, and a film having good balance of mechanical properties and thermal properties in the MD direction and the TD direction is obtained.

The above-mentioned thermoplastic liquid crystal polymer film comprises:
The degree of molecular orientation SOR in the longitudinal direction of the film is 1.03 to 1.
It is necessary to be in the range of 15. This thermoplastic liquid crystal polymer film has a good balance of mechanical properties and thermal properties in the MD direction and the TD direction, and is advantageous not only in high practicality but also in dimensional stability of the obtained film. is there.

Here, the degree of molecular orientation SOR (Segment Orie
The term “ntation ratio” refers to an index that gives the degree of molecular orientation of a segment constituting a molecule, and is a conventional M
Unlike OR (Molecular Orientation Ratio), it is a value in consideration of the thickness of the object. This molecular orientation degree SOR
Is calculated as follows.

First, using a well-known microwave molecular orientation measuring instrument, a thermoplastic liquid crystal polymer film is inserted into the microwave resonant waveguide such that the film surface is perpendicular to the direction of microwave propagation. The electric field intensity (microwave transmission intensity) of the microwave transmitted through the film is measured.

Then, based on the measured value, an m value (referred to as a refractive index) is calculated by the following equation. m = (Zo / △ z) X [1-νmax / νo] where Zo is a device constant, Δz is the average thickness of the object, and νmax
Is the frequency that gives the maximum microwave transmission intensity when the frequency of the microwave is changed, and vo is the frequency that gives the maximum microwave transmission intensity when the average thickness is zero (that is, when there is no object).

Next, when the rotation angle of the object with respect to the vibration direction of the microwave is 0 °, that is, the vibration direction of the microwave and the direction in which the molecules of the object are most oriented (usually,
M ₀ when the direction that gives the minimum microwave transmission intensity is the same as the m value, and the m value when the rotation angle is 90 ° is m ₉₀ , which is the longitudinal direction of the extruded film. The molecular orientation degree SOR is calculated by m ₀ / m ₉₀ .

The required degree of molecular orientation SOR is naturally different depending on the application field of the thermoplastic liquid crystal polymer film of the present invention, but SOR ≧ 1.50 and SOR ≦ 1.00.
In the case of (1), the alignment of the thermoplastic liquid crystal polymer molecules is remarkably biased, so that the molecules are easily torn in the alignment direction. In order to obtain a modified thermoplastic liquid crystal polymer film having good dimensional stability, the SOR needs to be in the range of 1.03 to 1.15. In particular, in applications where it is necessary to almost eliminate warpage during heating, it is desirable that the SOR is 1.03 to 1.08.

The thermoplastic liquid crystal polymer film used in the present invention may have any thickness, and includes a plate or sheet having a thickness of 1 mm or less. However, in the case of a coverlay film used as a protective layer of a wiring circuit of an electrically insulating substrate, the thickness of the film is 20 to 150.
It is preferably in the range of μm, more preferably in the range of 25 to 50 μm. When the thickness of the film is too thin, the rigidity and strength of the film are reduced, and the film is easily wrinkled during handling. If the thickness of the film is too large, the film is deformed when bonded so as to cover the wiring circuit, and the positional accuracy of the wiring is deteriorated, which causes a failure. The film may contain additives such as a lubricant and an antioxidant.

In the first invention, first, the first
In the process, the above-mentioned thermoplastic liquid crystal polymer film and metal foil are used, and these are pressed between heating rolls to form a laminate. As the heating roll, for example, a pair of heat-resistant rubber rolls and a heating metal roll are used, and a film and a metal foil are supplied between these rolls so as to be pressure-bonded. Thereafter, in a second step, the laminate obtained in the first step is passed between a metal roll heated to a temperature equal to or higher than the melting point of the thermoplastic liquid crystal polymer film and a heat-resistant rubber roll. Is applied. Further, after the first and second steps are completed, in the third step, the metal foil is peeled off from the laminated body, whereby the anisotropy is eliminated and the adhesive force to the adhesive which does not cause in-layer peeling is reduced. An excellently modified thermoplastic liquid crystal polymer film is obtained.

In the second invention, after the first step similar to that of the first invention is completed, a heating furnace such as a hot air circulating dryer is used as a second step, and the temperature is changed to a thermoplastic liquid crystal polymer film. Is adjusted to a temperature equal to or higher than the melting point of the laminate, and heat treatment is performed inside the laminate under no pressure. And this first
After the completion of the second step and the third step, the metal foil is peeled from the laminate to obtain a modified thermoplastic liquid crystal polymer film in the same manner as in the first invention. As described above, in the second step, by using a heating furnace, the entire laminate is heated at a uniform temperature.
Good reforming treatment can be performed.

The first and second embodiments of the first invention described above.
The heat-resistant rubber roll used in the step and the first step of the second invention preferably has a hardness of 80 degrees or more, more preferably 80 to 95 degrees, by an A-type spring hardness tester based on JIS K6301. used. The rubber having a temperature of 80 ° or more can be obtained by adding a vulcanization accelerator such as a vulcanizing agent or an alkaline substance to a synthetic rubber or a natural rubber such as a silicone rubber or a fluorine rubber. At this time, if the hardness is less than 80 degrees, the adhesive strength of the laminate is reduced due to insufficient pressure at the time of thermocompression bonding, which may cause inconvenience such as peeling off a part of the end of the laminate during the modification treatment. is there. On the other hand, if it exceeds 95 degrees, local linear pressure is applied between the heated metal roll and the heat-resistant rubber roll, which may cause poor appearance of the laminate. Then, in the second step of the first invention, heat-resistant rubber rolls having different hardnesses as described above are arbitrarily selected to control conditions for pressing the laminate.

In the second step of the first invention, when the laminate is passed between the heat-resistant rubber roll and the heating roll, it is necessary to apply a pressure of 5 to ²⁰ kg / cm ² to the laminate. is there. At this time, if it is less than 5Kg / cm ^2, the adhesive strength of the obtained film becomes insufficient pressure becomes insufficient, whereas, if it exceeds 20 Kg / cm ² is
This causes an inconvenience that the pressure is excessive and the metal foil cannot be peeled off from the film satisfactorily. Therefore, the pressure condition on the laminate is in the above range.

The above-mentioned thermoplastic liquid crystal polymer film comprises:
During the heating in the first and second steps in each invention, the coefficient of thermal expansion changes, so that the SOR of the thermoplastic liquid crystal polymer film is adjusted in advance in consideration of this point, and the lamination conditions with the metal foil, etc. It is necessary to design a manufacturing process such as adjusting the process.

In the second step of each invention, when modifying the laminate obtained in the first step, it is necessary to carry out the modification at a temperature not lower than the melting point of the thermoplastic liquid crystal polymer film, and it is particularly preferable. It is performed in the range from the melting point to the melting point + 30 ° C. In this case, the film in which the anisotropy of the film is eliminated by the heat treatment in the second step and the adhesive strength to the adhesive is increased. At this time, when the melting point is lower than the melting point, the anisotropy of the obtained film is insufficiently improved. On the other hand, if the melting point is higher than + 30 ° C., the temperature approaches the decomposition temperature of the thermoplastic liquid crystal polymer film, so that the appearance such as coloring deteriorates, which is not desirable.

Further, the metal foil used in each invention is not particularly limited, but is preferably a metal having a toughness that can be easily and reliably peeled off from the laminate, such as aluminum, iron, copper and silver. , Nickel, or alloys thereof. Since these metals have high thermal conductivity, the film temperature can be quickly raised to a desired temperature, and the time required for the modification treatment can be shortened. Further, as the metal foil, any one produced by a rolling method, an electrolysis method, or the like can be used, but one produced by a rolling method having a small surface roughness has an adhesion to the modified adhesive. This is preferable because a thermoplastic liquid crystal polymer film having high strength can be obtained.
As the form of the metal foil, a planar shape is preferable in terms of easy prevention of the flow of the thermoplastic liquid crystal polymer film which has been softened and melted during heating and ease of handling when the film is peeled off. Particularly preferred metal foils include rolled aluminum foils in terms of economy and handling. The thickness of the metal foil is preferably in the range of 9 to 200 μm, more preferably in the range of 9 to 75 μm.

The surface roughness of the metal foil is required to be in the range of 1 to 3 μm because it is related to the adhesive strength of the modified thermoplastic liquid crystal polymer film to the adhesive. The surface roughness of the metal foil is defined by the maximum roughness (Rmax) specified in JISB0601. At this time, the maximum roughness is 1
When the thickness is less than μm, not only the thermoplastic liquid crystal polymer film is deformed during the heat treatment in the first and second steps, but also a sufficient adhesive strength to the adhesive may not be obtained after the modification. On the other hand, if the maximum roughness exceeds 3 μm, the adhesive strength to the adhesive does not increase so much, and the thermoplastic liquid crystal polymer film is easily broken in the step of peeling the metal foil, which is not preferable. Therefore, the surface roughness of the metal foil is in the above range. Also, conical projections, crater-like depressions, and scratch-like linear irregularities may be provided on the surface of the metal foil to make the surface roughness within the above range.

When a rolled aluminum foil is used as the metal foil, it is preferable to apply a rolled mineral oil to the surface of the rolled aluminum foil. By applying this to rolled aluminum foil,
When the aluminum foil is peeled from the modified thermoplastic liquid crystal polymer film, the peeling can be easily performed. As the rolled mineral oil, for example, (a) 30
Wt% or less, an alkyl phosphite (b) C ₁₂ ~C ₁₈ with those containing 10 wt% or less, which on the surface of the aluminum foil, in a range of 0.3~1.8mg / m ² It is preferred to apply. At this time, the applied amount is 0.3 mg / m
If it is less than ^{2, the} aluminum foil cannot be easily peeled from the laminate after the modification treatment, and the film may be broken at the end.
On the other hand, when the coating amount exceeds 1.8 mg / m ² , the rolled mineral oil volatilizes with the heat treatment, and this may be contained as bubbles between the aluminum foil and the thermoplastic liquid crystal polymer film. The appearance of the obtained thermoplastic liquid crystal polymer film may be deteriorated. Therefore, it is preferable that the applied amount of the rolled mineral oil be in the above range. Further, the type of the fatty acid monoester and the type of the alkyl group of the alkyl phosphite can be selected depending on the reforming treatment temperature.

In the present invention, a coverlay film can be obtained by applying a thermosetting adhesive to the thermoplastic liquid crystal polymer film obtained as described above and drying it. At this time, an acrylic, phenolic, or epoxy thermosetting adhesive can be used as the adhesive. Particularly, in order to exhibit the flexibility of the thermoplastic liquid crystal polymer film, an epoxy-based film is suitable. Additives may be added to these adhesives to impart properties such as flame retardancy.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In the following Reference Examples, Examples and Comparative Examples, the melting point of the thermoplastic liquid crystal polymer film,
The film thickness, appearance, surface roughness, adhesive strength of the laminate, and adhesive strength with the adhesive were measured by the following methods.

(1) Melting Point The melting point was obtained by observing the thermal behavior of the film using a differential scanning calorimeter. That is, after the temperature of the test film is raised at a rate of 20 ° C./min to completely melt it, the melt is rapidly cooled to 50 ° C. at a rate of 50 ° C./min, and the temperature is raised again at a rate of 20 ° C./min. The position of the endothermic peak that appeared when the recording was performed was recorded as the melting point of the film.

(2) Film Thickness Using a digital thickness meter (LVDT, manufactured by Mitutoyo Corporation), the obtained film was measured at 10 points at 1 cm intervals in the TD direction, and the average value was taken as the film thickness.

(3) Surface roughness (Rmax) Measured according to JIS B0601. That is, it was calculated from a cross-sectional curve of a film measured using a stylus type surface roughness measuring device manufactured by Rank Taylor Bobson Co., Ltd. under the conditions of a needle tip radius of curvature of 2 μm and a load of 20 mg.

(4) Appearance The appearance was visually observed. Then, those having no swelling or wrinkles were regarded as excellent, those having some swelling or wrinkles, etc., were regarded as good, and those which could not be commercialized with large swelling, wrinkles, etc., were regarded as poor.

(5) Adhesive strength of laminate A peel test specimen having a width of 1.5 cm was prepared from the laminate, and the film layer was fixed on a flat plate with a double-sided adhesive tape.
According to 5016, the metal foil is 50 mm by the 180 ° method.
The strength at the time of peeling at a speed of / min was measured.

(6) Adhesive Strength with Adhesive An epoxy adhesive (Alon Mighty BX-60, manufactured by Toa Gosei Chemical Industry Co., Ltd.)
m, and both sides have a surface roughness of 10
μm electrolytic copper foil was bonded to the rough surface,
A peel test sample was prepared by curing in a hot press for minutes. Then, a test piece having a width of 10 mm was cut out from the peel test sample, and a 90 ° peel test was performed in accordance with JIS C6471. In this test, one side of the test piece is adhered to a support plate with a double-sided adhesive tape, and the force when the copper foil on the opposite surface is peeled off by pulling at a speed of 50 mm / min in a direction perpendicular to the support plate.

REFERENCE EXAMPLE 1 A thermoplastic liquid crystal polymer having a melting point of 283 ° C., which is a copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, is melt-extruded and has a film thickness of 50 μm by inflation molding. A film having a degree of molecular orientation SOR of 1.05 was obtained. This thermoplastic liquid crystal polymer film
And

REFERENCE EXAMPLE 2 A thermoplastic liquid crystal polymer having a melting point of 280 ° C., which is a copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, is melt-extruded. A film having a degree of molecular orientation SOR of 1.03 was obtained. This thermoplastic liquid crystal polymer film is
And

REFERENCE EXAMPLE 3 A thermoplastic liquid crystal polymer having a melting point of 280 ° C., which is a copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, is melt-extruded. A film having a molecular orientation degree SOR of 1.50 was obtained. This thermoplastic liquid crystal polymer film is
And

REFERENCE EXAMPLE 4 A thermoplastic liquid crystal polymer having a melting point of 280 ° C., which is a copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, is melt-extruded. A film having a molecular orientation degree SOR of 1.00 was obtained. This thermoplastic liquid crystal polymer film is
And

Example 1 Thermoplastic liquid crystal polymer film A obtained in Reference Example 1
And a rolled aluminum foil having a thickness of 50 μm and a surface roughness of 2.3 μm. In this case, the aluminum foil, 28 wt% of the fatty acid monoester to the surface, the rolling mineral oil containing C ₁₆ alkyl phosphites 8 wt%, 1.3 mg / m
² was applied. In the first step, a heat-resistant rubber roll (hardness: 90 degrees) and a heated metal roll are attached to the continuous heat roll press, and the thermoplastic liquid crystal polymer film A is rolled on the heat-resistant rubber roll. The aluminum foil was supplied between the rolls so that they contacted each other. Further, a heating metal roll was controlled at 260 ° C., and a pressure of 15 kg / cm ² was applied by a rubber roll to produce a laminate having a structure of thermoplastic liquid crystal polymer film / rolled aluminum foil. Subsequently, in the second step,
Using the same apparatus as above, the laminated body obtained in the first step was supplied so that the rolled aluminum foil was in contact with the heated metal roll surface controlled at 300 ° C. and the thermoplastic liquid crystal polymer film was in contact with the heat-resistant rubber roll surface. , Heat resistant rubber roll 1
The reforming treatment was performed by applying a pressure of ² kg / cm ² . As a result, the adhesive strength of the obtained laminate was 0.25 kg / cm.
Met. Further, in the third step, the rolled aluminum foil could be easily peeled from the laminate, and a modified film having a good appearance was obtained after the peeling. The adhesive strength of this film to the adhesive was 0.9 kg / cm. Table 6 shows the results.

Example 2 Thermoplastic liquid crystal polymer film B obtained in Reference Example 2
And rolled aluminum foil with a thickness of 50 μm and a surface roughness of 1.8 μm
Was used. At this time, the rolled aluminum foil has
25% by weight of fatty acid monoester, C₁₈Alkyl phosphorous acid
0.5 mg of a rolled mineral oil containing 7% by weight of an ester
/ M^TwoAt a rate of And in the first step,
Using a continuous hot roll press as in Example 1,
The heat-resistant rubber roll has a hardness of 85 degrees and a pressure bonding temperature of 260 ° C.
Pressure 10Kg / cm^TwoTo produce a laminate. Also,
In the second step, a heating temperature of 300 ° C. and a pressure of 8 kg /
cm ^TwoAnd As a result, the adhesive strength of the obtained laminate is
It was 0.35 kg / cm. In the third step,
The rolled aluminum foil can be easily peeled from this laminate,
After peeling, a modified film having a good appearance was obtained. This file
The adhesive strength of the film to the adhesive is 0.8 kg / cm
there were. Table 6 shows the results.

Example 3 Thermoplastic liquid crystal polymer film A obtained in Reference Example 1
And a rolled aluminum foil having a thickness of 50 μm and a surface roughness of 2.3 μm. In this case, the rolled aluminum foil, 28 wt% of the fatty acid monoester to the surface, the rolling mineral oil containing C ₁₆ alkyl phosphites 8 wt%, 1.3 mg
/ M ² . Then, in the first step, a laminate was produced using the same continuous hot roll press as in Example 1 at a compression temperature of 260 ° C. and a pressure of 10 kg / cm ² . In the second step, the laminate obtained in the first step was suspended in a hot-air circulating dryer controlled at 300 ° C., and subjected to a modification treatment for 5 minutes. As a result, the adhesive strength of the obtained laminate was 0.25 kg / cm. In the third step, when the thermoplastic liquid crystal polymer film was peeled from the laminate, a film having an excellent appearance was obtained. The adhesive strength of this film to the adhesive is 1.2 kg / cm.
Met. Table 6 shows the results.

Example 4 Thermoplastic liquid crystal polymer film B obtained in Reference Example 2
And a rolled aluminum foil having a thickness of 50 μm and a surface roughness of 1.8 μm. At this time, 0.5 mg of a rolled mineral oil containing 28% by weight of a fatty acid monoester and 7% by weight of a _C18 alkyl phosphite on the surface of the rolled aluminum foil.
/ M ² . Then, a hot-air heat treatment furnace was attached to the continuous hot roll press device of Example 1, and in the first step, a pressure bonding temperature of 260 ° C. and a pressure of 10 kg / cm ^2.
A laminate was produced under the following conditions. In the second step,
The reforming treatment was performed at a treatment temperature of 300 ° C. for 10 seconds continuously from the first step. As a result, the adhesive strength of the obtained laminate was
It was 0.35 kg / cm. In the third step, when the thermoplastic liquid crystal polymer film was peeled from the laminate, a film having an excellent appearance was obtained. The adhesive strength of this film to the adhesive was 1.2 kg / cm. Table 6 shows the results. From this, it can be understood that a thermoplastic liquid crystal polymer film having a high adhesive strength to the adhesive can be obtained even with an apparatus that performs the pressure bonding and the modification treatment continuously. That is, by performing continuous processing, a modified film can be obtained at low cost.

Comparative Example 1 A rolled aluminum foil was peeled from the laminate without performing the second step of Example 1 to obtain a film. At this time, the adhesive strength of the laminate was extremely low at 0.15 kg / cm, and the laminate could be easily peeled off. The adhesive strength of the peeled film to the adhesive was extremely low at 0.2 kg / cm, which was insufficient for practical use. Table 6 shows the results.

Comparative Example 2 A laminate was produced in the same manner as in Example 4, except that the thermoplastic liquid crystal polymer film C obtained in Reference Example 3 was used, and a rolled aluminum foil treated in the same manner as in Example 4 was used. Obtained. At this time, the adhesive strength of the laminate was 0.33, which was almost the same as that of Example 4.
However, when the rolled aluminum foil was peeled off, the end of the film was cracked and the appearance was poor. Although good results were obtained with an adhesive strength of 1.2 Kg / cm for the adhesive having no breakage, practical application was not possible due to poor appearance. Table 6 shows the results.

Comparative Example 3 Thermoplastic Liquid Crystal Polymer Film A Obtained in Reference Example 1
And a gloss rolled copper foil having a thickness of 18 μm and a surface roughness of 0.5 μm was used to obtain a laminate in the same manner as in Example 4. At this time, the adhesive strength of the laminate was extremely low at 0.15 Kg / cm, and the laminate could be easily peeled off. However, small bubbles were confirmed at the end, and the appearance was poor. Further, the adhesive strength of the peeled film to the adhesive is as extremely low as 0.4 kg / cm, which is insufficient for practical use. Table 6 shows the results.

Comparative Example 4 Thermoplastic Liquid Crystal Polymer Film A Obtained in Reference Example 1
And an electrolytic copper foil having a thickness of 18 μm and a surface roughness of 8.0 μm, to obtain a laminate in the same manner as in Example 4. At this time, the adhesive strength of the laminate was extremely high at 1.4 kg / cm, and the copper foil could not be peeled over the entire width of the film, so that a test film could not be collected. Therefore, it was impossible to evaluate the appearance, and the adhesive strength to the adhesive could not be measured.
Table 6 shows the results.

Comparative Example 5 Thermoplastic liquid crystal polymer film D obtained in Reference Example 4
And the rolled aluminum foil used in Example 3 to obtain a laminate in the same manner as in Example 3. At this time, the adhesive strength of the laminate was 0.27 kg / cm, which was almost the same as in Example 3. However, when the rolled aluminum foil was peeled off, the film was easily torn in the width direction, and tearing of several mm width caused stress Since it was generated intermittently in the central part where concentration is likely to occur and stable peeling was not possible, the appearance was poor. Although good results were obtained with an adhesive force of 1.2 Kg / cm for the adhesive having no breakage, it could not be put to practical use due to poor appearance. Table 6 shows the results.

[0063]

[Table 6]

As is clear from Table 6, the thermoplastic liquid crystal polymer films obtained in Comparative Examples 1 to 5 have low adhesion to the adhesive and are difficult to put into practical use due to poor appearance. Examples 1 to 4 according to the present invention have a high adhesive strength to the adhesive and a good appearance.

[0065]

As described above, according to the present invention, a thermoplastic liquid crystal polymer film and a cover lay film having various excellent properties derived from a thermoplastic liquid crystal polymer and having a high adhesive force to an adhesive are provided. It can be obtained at low cost.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C08L 67:00 F term (reference) 4F073 AA01 BA23 BB01 GA01 GA11 4F209 AA24B AC07 AF01 AG01 AG05 PA04 PB02 PC05 PG14 PN03 PN06 PQ02

Claims (5)

[Claims] 1. A thermoplastic liquid crystal polymer film having a degree of molecular orientation SOR in the longitudinal direction of the film in the range of 1.03 to 1.15, and a maximum surface roughness (Rmax; JISB060).
1) pressing a metal foil having a thickness in the range of 1 to 3 μm between heating rolls to form a laminate; and using a roll heated to a temperature equal to or higher than the melting point of the thermoplastic liquid crystal polymer film. A method for modifying a thermoplastic liquid crystal polymer film, comprising: a second step of performing a modification treatment at a pressure of 5 to ²⁰ kg / cm ² ; and a third step of removing a metal foil from the laminate. 2. A thermoplastic liquid crystal polymer film having a degree of molecular orientation SOR in the longitudinal direction of the film in the range of 1.03 to 1.15, and a maximum surface roughness (Rmax; JISB060).
A) a step of pressing a metal foil having a thickness in the range of 1 to 3 μm between heating rolls to form a laminate, and heating the laminate to a temperature equal to or higher than the melting point of the thermoplastic liquid crystal polymer film. A method for modifying a thermoplastic liquid crystal polymer film, comprising: a second step of heating and modifying in a non-pressurized state, and a third step of peeling a metal foil from the laminate. 3. The method according to claim 1, wherein the metal foil comprises: (a) 30% by weight or less of a fatty acid monoester;
Rolled mineral oil containing not more than 10% by weight of _{12- C18} alkyl phosphite is coated on the surface with 0.3-1.8 mg / m ^2.
A method for modifying a thermoplastic liquid crystal polymer film, wherein the method is a rolled aluminum foil applied in the range described above. 4. A thermoplastic liquid crystal polymer film obtained according to claim 1, 2 or 3. 5. A coverlay film obtained by applying an adhesive to the thermoplastic liquid crystal polymer film obtained in claim 4.